JP2023123508A - Improved attribute layer and signaling in point cloud coding - Google Patents

Abstract

To provide an encoder, a decoder, and a method implemented by them.SOLUTION: A method for encoding a point cloud coding (PCC) video sequence includes receiving a bitstream comprising a plurality of coded sequences of PCC frames. The plurality of coded sequences of PCC frames represent a plurality of PCC attributes including geometry, texture, and one or more of reflectance, transparency, and normal. Each coded PCC frame is represented by one or more PCC network abstraction layer (NAL) units. The method also includes: parsing the bitstream to obtain, for each PCC attribute, an indication of one of a plurality of video coder/decoders (codecs) used to code the corresponding PCC attribute; and decoding the bitstream based on the indicated video codecs for the PCC attributes.SELECTED DRAWING: Figure 11

Description

This patent application is a U.S. provisional patent entitled "High-Level Syntax Designs for Point Cloud Coding," filed September 14, 2018 by Ye-Kui Wang et al. The benefit of application Ser. No. 62/731,693 is claimed.

TECHNICAL FIELD This disclosure relates generally to video coding, and specifically to coding video attributes for point cloud coding (PCC) video frames.

The amount of video data required to show a relatively short video is substantial and the data is streamed or otherwise communicated over communication networks with limited bandwidth capacity. It can cause difficulties when Therefore, video data is generally compressed before being communicated over modern telecommunication networks. The size of the video can also be an issue when the video is stored on a storage device, as memory resources may be limited. Video compression devices often use software and/or hardware at the source to encode video data prior to transmission or storage, thereby reducing the amount of data required to represent a digital video image. Decrease. The compressed data is then received at the destination by a video decompression device that decodes the video data. With limited network resources and ever-increasing demands for higher video quality, improved compression and decompression techniques that improve compression ratios while sacrificing little image quality are desirable.

According to one embodiment, the present disclosure includes a method implemented by a video decoder. The method is receiving, by a receiver, a bitstream containing a coded sequence of multiple point cloud coding (PCC) frames, the coded sequence of multiple PCC frames being geometrically Each coded PCC frame represents one or more PCC Network Abstraction Layer (NAL) units representing shape, texture, and multiple PCC attributes including one or more of reflectance, transparency, and normal including receiving, represented by The method further comprises, by the processor, for each PCC attribute, a bitstream to obtain an indication of one of a plurality of video coder decoders (codecs) used to encode the corresponding PCC attribute. including parsing the The method further includes decoding, by the processor, the bitstream based on the indicated video codec for the PCC attributes. In some video coding systems, an entire sequence of PCC frames is coded using a single codec. A PCC frame may contain multiple PCC attributes. Some video codecs may be more efficient at encoding some PCC attributes than others. This embodiment allows different video codecs to encode different PCC attributes for the same sequence of PCC frames. The present embodiment also provides various syntax elements to support coding flexibility when a PCC frame in a sequence uses multiple PCC attributes (eg, three or more). By providing more attributes, the encoder can encode more complex PCC frames. Additionally, the decoder can decode and display more complex PCC frames. Furthermore, by allowing different codecs to be employed for different attributes, the coding process can be optimized based on codec selection. This may reduce processor resource usage at both the encoder and decoder. Furthermore, it may support increased compression and coding efficiency, which reduces memory usage and network resource usage while transmitting bitstreams between encoders and decoders.

Optionally, in any of the preceding aspects, in another implementation of the aspect, each sequence of PCC frames is associated with a sequence-level data unit comprising sequence-level parameters, the sequence-level data unit comprising: including a first syntax element indicating that one attribute was coded by a first video codec and indicating that a second attribute was coded by a second video codec.

Optionally, in any of the foregoing aspects, another implementation of the aspects provides that the first syntax element is an identified_codec_for_attribute element included in a group of frame headers in the bitstream.

Optionally, in any of the preceding aspects, in another implementation of the aspect, the first attribute is organized into a plurality of streams and the second syntax element is a bitstream associated with the first attribute. , indicating the stream membership for the data unit of the .

Optionally, in any of the preceding aspects, in another implementation of the aspect, the first attribute is organized into multiple layers and the third syntax element is a bitstream associated with the first attribute. indicates the layer membership for the data units of the .

Optionally, in any of the preceding aspects, in another implementation of the aspect, the second syntax element is a num_streams_for_attribute element included in a group of frame headers in the bitstream and the third syntax element is the bit num_layers_for_attribute element contained in a group of frame headers in a stream.

Optionally, in any of the preceding aspects, in another implementation of the aspect, the fourth syntax element comprises data associated with a point cloud in which a first of the plurality of layers is irregular Including, providing.

Optionally, in any of the foregoing aspects, another implementation of the aspect provides that the fourth syntax element is a regular_points_flag element included in a group of frame headers in the bitstream.

Optionally, in any of the preceding aspects, another implementation of the aspect is that the bitstream is decoded into a decoded sequence of PCC frames; including forwarding to a display for.

According to one embodiment, this disclosure includes a method implemented in a video encoder. The method is encoding, by a processor, a plurality of PCC attributes of a sequence of PCC frames into a bitstream with a plurality of coder-decoders (codecs), the plurality of PCC attributes being geometry, texture, and one or more of reflectance, transmittance, and normal, and each coded PCC frame is represented by one or more PCC network abstraction layer (NAL) units, encoding Including. The method further includes, by the processor, encoding for each PCC attribute an indication of one of the video codecs used to encode the corresponding PCC attribute. The method further includes transmitting, by the transmitter, the bitstream towards the decoder. In some video coding systems, an entire sequence of PCC frames is coded using a single codec. A PCC frame may contain multiple PCC attributes. Some video codecs may be more efficient at encoding some PCC attributes than others. This embodiment allows different video codecs to encode different PCC attributes for the same sequence of PCC frames. The present embodiment also provides various syntax elements to support coding flexibility when a PCC frame in a sequence uses multiple PCC attributes (eg, three or more). By providing more attributes, the encoder can encode more complex PCC frames. Additionally, the decoder can decode and display more complex PCC frames. Furthermore, by allowing different codecs to be employed for different attributes, the coding process can be optimized based on codec selection. This may reduce processor resource usage at both the encoder and decoder. Furthermore, it may support increased compression and coding efficiency, which reduces memory usage and network resource usage while transmitting bitstreams between encoders and decoders.

Optionally, in any of the preceding aspects, in another implementation of the aspect, each sequence of PCC frames is associated with a sequence-level data unit comprising sequence-level parameters, the sequence-level data unit comprising: including a first syntax element indicating that one PCC attribute was coded by a first video codec and indicating that a second PCC attribute was coded by a second video codec. do.

Optionally, in any of the foregoing aspects, another implementation of the aspects provides that the first syntax element is an identified_codec_for_attribute element included in a group of frame headers in the bitstream.

Optionally, in any of the preceding aspects, in another implementation of the aspect, the first attribute is organized into a plurality of streams and the second syntax element is a bitstream associated with the first attribute. , indicating the stream membership for the data unit of the .

Optionally, in any of the preceding aspects, in another implementation of the aspect, the first attribute is organized into multiple layers and the third syntax element is a bitstream associated with the first attribute. indicates the layer membership for the data units of the .

Optionally, in any of the preceding aspects, in another implementation of the aspect, the second syntax element is a num_streams_for_attribute element included in a group of frame headers in the bitstream and the third syntax element is the bit num_layers_for_attribute element contained in a group of frame headers in a stream.

Optionally, in any of the preceding aspects, in another implementation of the aspect, the fourth syntax element comprises data associated with a point cloud in which a first of the plurality of layers is irregular Including, providing.

Optionally, in any of the foregoing aspects, another implementation of the aspect provides that the fourth syntax element is a regular_points_flag element included in a group of frame headers in the bitstream.

In one embodiment, the disclosure includes a processor, a receiver coupled to the processor, and a transmitter coupled to the processor, wherein the processor, receiver, and transmitter are any of the preceding aspects. configured to carry out the method.

In one embodiment, the present disclosure is a non-transitory computer-readable medium containing a computer program product for use by a video coding device, the computer program product being a computer program product that, when executed by a processor, causes the video coding device to perform the aforementioned operations. It includes a non-transitory computer-readable medium containing computer-executable instructions stored on the non-transitory computer-readable medium to perform the method of any of the aspects.

In one embodiment, the present disclosure is encoding multiple PCC attributes of a sequence of PCC frames into a bitstream with multiple coder-decoders (codecs), wherein the multiple PCC attributes are geometric shapes, A code that includes texture and one or more of reflectance, transmittance, and normal, with each coded PCC frame represented by one or more PCC network abstraction layer (NAL) units an encoder including first attribute encoding means and second attribute encoding means for performing encoding. The encoder further includes syntax encoding means for encoding, for each PCC attribute, an indication of one of the video codecs used to encode the corresponding PCC attribute. The encoder further includes transmitting means for transmitting the bitstream towards the decoder.

Optionally, in any of the preceding aspects, another implementation of the aspect provides that the encoder is further configured to perform the method of any of the preceding aspects.

In one embodiment, the present disclosure is to receive a bitstream that includes a coded sequence of multiple PCC frames, the coded sequence of multiple PCC frames including geometry, texture, and a plurality of PCC attributes including one or more of reflectance, transparency, and normal, and each coded PCC frame is represented by one or more PCC network abstraction layer (NAL) units , a decoder including receiving means for performing receiving. The decoder further parses the bitstream to obtain, for each PCC attribute, an indication of one of a plurality of video coder decoders (codecs) used to code the corresponding PCC attribute. including analysis means for performing The decoder further includes decoding means for performing decoding of the bitstream based on the indicated video codec for the PCC attribute.

Optionally, in any of the foregoing aspects, there is provided that another implementation of the aspect is further configured to perform the method of any of the foregoing aspects.

For clarity, any one of the aforementioned embodiments may be combined with any one or more of the other aforementioned embodiments to create new embodiments within the scope of the present disclosure.

These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.

For a more complete understanding of the present disclosure, reference is made to the following brief description in conjunction with the accompanying drawings and detailed description. Here, like reference numbers refer to like parts.

4 is a flowchart of an exemplary method of coding a video signal; 1 is a schematic diagram of an exemplary coding and decoding (codec) system for video coding; FIG. 1 is a schematic diagram of an exemplary video encoder; FIG. 1 is a schematic diagram of an exemplary video decoder; FIG. Fig. 3 is an example of a point cloud medium that can be encoded according to the PCC scheme; FIG. 4 is an example of data segmentation and packing for point cloud media frames; FIG. FIG. 4B is a schematic diagram showing an exemplary PCC video stream with an extended set of attributes; FIG. 4 is a schematic diagram showing an exemplary mechanism for encoding PCC attributes with multiple codecs; FIG. 4 is a schematic diagram showing an example of an attribute layer; FIG. FIG. 4 is a schematic diagram illustrating an example attribute stream; 4 is a flowchart of an exemplary method for encoding a PCC video sequence with multiple codecs; 4 is a flowchart of an exemplary method for decoding a PCC video sequence with multiple codecs; 1 is a schematic diagram of an exemplary video coding device; FIG. 1 is a schematic diagram of an exemplary system for coding a PCC video sequence with multiple codecs; FIG. 4 is a flowchart of another exemplary method of coding a PCC video sequence with multiple codecs; 4 is a flowchart of another exemplary method for decoding a PCC video sequence with multiple codecs;

Initially, exemplary implementations of one or more embodiments are provided below, although the disclosed systems and/or methods may incorporate any number of techniques, whether currently known or in existence. It should be understood that it can be implemented using The present disclosure should in no way be limited to the exemplary implementations, drawings and techniques hereinafter, including the exemplary designs and implementations illustrated and described herein, but within the scope of the appended claims. ranges may be modified along with their full range of equivalents.

Many video compression techniques can be used to reduce the size of video files with minimal data loss. For example, video compression techniques can include performing temporal (eg, intra-picture) prediction and/or temporal (eg, inter-picture) prediction to reduce or remove data redundancy in a video sequence. can. For block-based video coding, a video slice (e.g., a video picture or portion of a video picture) may be partitioned into video blocks, which are treeblocks, coding tree blocks (CTBs), coding tree blocks (CTBs), and coding tree blocks (CTBs). It may also be called a tree unit (CTU), coding unit (CU), and/or coding node. Video blocks in an intra-coded (I) slice of a picture are coded using spatial prediction with respect to reference samples in neighboring blocks within the same picture. A video block in an inter-coded (P or B) slice of a picture employs spatial prediction with respect to reference samples in neighboring blocks in the same picture, or temporal prediction with respect to reference samples in other reference pictures: may be coded. A picture is called a frame and a reference picture is called a reference frame. Spatial prediction or temporal prediction results in a prediction block representing the image block. Residual data represents pixel differences between the original image block and the prediction block. Thus, an inter-coded block is encoded according to motion vectors pointing to blocks of reference samples forming the predictive block and residual data indicating the difference between the coded block and the predictive block. Intra-coded blocks are encoded according to an intra-coding mode and residual data. For further compression, the residual data may be transformed from the pixel domain to the transform domain. These yield residual transform coefficients, which may be quantized. The quantized transform coefficients may first be arranged in a two-dimensional array. The quantized transform coefficients may be scanned to produce a one-dimensional vector of transform coefficients. Entropy coding may be applied to achieve more compression. Such video compression techniques are discussed in more detail below.

To ensure that the encoded video is decoded correctly, the video is encoded and decoded according to corresponding video coding standards. The video coding standard is the International Telecommunications Union (ITU) Standardization Sector (ITU-T) H.264 standard. 261, International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) Moving Picture Experts Group (MPEG)-1 Part 2, ITU-T H.261. 262, or ISO/IEC MPEG-2 Part 2, ITU-T H.262. 263, ISO/IEC MPEG-4 Part 2, ITU-T H.263. Advanced Video Coding (AVC), also called ISO/IEC MPEG-4 Part 10, and ITU-T H.264 or ISO/IEC MPEG-4 Part 10; H.265 or MPEG-H Part 2, also known as High Efficiency Video Coding (HEVC). AVC includes scalable video coding (SVC), multiview video coding (MVC) and multiview video coding plus depth (MVC+D), and three-dimensional (3D) AVC (3D-AVC). Including extensions. HEVC includes extensions such as scalable HEVC (SHVC), multi-view HEVC (MV-HEVC), and 3D HEVC (3D-HEVC). The ITU-T and ISO/IEC Joint Video Experts Team (JVET) initiated the development of a video coding standard called Versatile Video Coding (VVC).VVC is included in the Working Draft (WD), This includes JVET-K1001-v4 and JVET-K1002-v1.

PCC is a mechanism for coding video of 3D objects. A point cloud is a set of data points in 3D space. Such data points include, for example, parameters that determine spatial position and color. Point clouds are used for real-time 3D immersive telepresence, content virtual reality (VR) viewing with interactive parallax, 3D free viewpoint sports relay broadcasts, geographic information systems, cultural heritage, large-scale 3D dynamic It may be used in various applications such as map-based autonomous navigation, automotive applications, and so on. ISO/IEC MPEG codecs for PCC may operate on lossless and/or lossy compression point clouds with substantial coding efficiency and robustness to network environments. Using this codec, point clouds can be manipulated as a form of computer data, stored on various storage media, transmitted and received over networks, and distributed over broadcast channels. PCC coding environments are classified into PCC Category 1, PCC Category 2, and PCC Category 3. This disclosure is directed to PCC Category 2, which relates to MPEG output documents N17534 and N17533. The design of the PCC Category 2 codec seeks to leverage other video codecs to compress the geometry and texture information of dynamic point clouds by compressing the point cloud data as a set of different video sequences. aim. For example, two video sequences, one representing the geometry information of the point cloud data and the other representing the texture information, can be generated and compressed using one or more video codecs. Additional metadata supporting interpretation of the video sequence (eg, occupancy map and auxiliary patch information) can also be separately generated and compressed.

A PCC system may support geometry PCC attributes containing position data and texture PCC attributes containing color data. However, some video applications may include other types of data such as reflectance, transparency, normal vectors, and the like. Some of these types of data may be encoded more efficiently using some codecs than others. However, PCC systems may require that the entire PCC stream, and thus all PCC attributes, be encoded by the same codec. Furthermore, PCC attributes may be divided into multiple layers. Such layers may then be combined and/or encoded into one or more PCC attribute streams. For example, the layers of attributes can be coded according to a temporally interleaved coding scheme, where the first layer is coded in PCC Access Units (AUs) with even values of picture output order. and the second layer is coded in PCC AU with odd values of image output order. Proper identification of streams and layers can be a challenge, as there can be 0-4 streams for each attribute and various layer combinations of such streams. However, the PCC system may not be able to determine how many layers are coded or combined with the PCC attribute stream in a given PCC bitstream. Furthermore, PCC systems may not have mechanisms for indicating the scheme of layer combinations and/or indicating correspondence between such layers and PCC attribute streams. Finally, patches are employed to encode PCC video data. For example, a three-dimensional (3D) PCC object can be represented as a set of two-dimensional (2D) patches. This allows PCC to work with video codecs designed to encode 2D video frames. However, some points in the point cloud may not be captured by the patch in some cases. For example, an isolated point in 3D space may be difficult to code as part of a patch. The only patch that makes sense in such a case is a 1 pixel by 1 pixel patch containing a single point, which for many such points significantly increases the signaling overhead. Alternatively, an irregular point cloud can be used, which is a special patch containing multiple isolated points. A different approach is used for signaling attributes for irregular point cloud patches than for other patch types. However, the PCC system may not be able to indicate that the PCC attribute layer carries an irregular point cloud/patch.

Disclosed herein are mechanisms for improving PCC by addressing the above problems. In one embodiment, a PCC system may employ different codecs to encode different PCC attributes. Specifically, separate syntax elements can be employed to identify the video codec for each attribute. In another embodiment, the PCC system explicitly signals the number of layers that are coded and/or combined to represent each PCC attribute stream. Additionally, a PCC system may employ syntax elements to signal the modes used to encode and/or combine layers of PCC attributes within a PCC attribute stream. Additionally, the PCC system may employ syntax elements to specify the layer index of the layer associated with each data unit of the corresponding PCC attribute stream. In yet another embodiment, a flag can be employed for each PCC attribute layer to indicate whether the PCC attribute layer carries any irregular point cloud points. Such embodiments may be used alone or in combination. Moreover, such embodiments allow PCC systems to employ more complex coding schemes in a manner that is recognizable by, and therefore decodable by, decoders. These and other examples are described in detail below.

FIG. 1 is a flowchart of an exemplary method of operation 100 for coding a video signal. Specifically, a video signal is encoded with an encoder. The encoding process compresses the video signal by employing various mechanisms to reduce the video file size. Smaller file sizes allow compressed video files to be sent to users while reducing the associated bandwidth overhead. A decoder then decodes the compressed video file to reconstruct the original video signal for display to the end user. The decoding process generally mirrors the encoding process, allowing the decoder to consistently reconstruct the video signal.

At step 101, a video signal is input to an encoder. For example, the video signal may be an uncompressed video file stored in memory. As another example, a video file may be captured by a video capture device such as a video camera and encoded to support live streaming of the video. A video file may contain both audio and video components. A video component includes a sequence of image frames that, when viewed in sequence, give the impression of visual motion. A frame includes pixels represented in terms of light, referred to herein as luminance components (or luminance samples), and colors, referred to herein as chroma components (or color samples). In some examples, the frames may also include depth values to support three-dimensional viewing.

At step 103 the video is divided into blocks. Partitioning involves subdividing the pixels in each frame into square and/or rectangular blocks for compression. For example, in High Efficiency Video Coding (HEVC) (also known as H.265 and MPEG-H Part 2), a frame is first sized to a predetermined size (e.g., 64 pixels by 64 pixels). ) can be divided into coding tree units (CTUs). A CTU contains both luminance and chroma samples. A coding tree can be employed to partition the CTU into blocks, which can then be recursively subdivided until a configuration supporting further encoding is achieved. For example, the luminance component of a frame may be further divided until individual blocks contain relatively uniform illumination values. Additionally, the chroma component of the frame may be further divided until individual blocks contain relatively uniform color values. Therefore, the splitting mechanism varies depending on the content of the video frames.

At step 105 various compression mechanisms are employed to compress the image blocks divided at step 103 . For example, inter prediction and/or intra prediction may be employed. Inter-prediction is designed to take advantage of the fact that common scene objects tend to appear in consecutive frames. Therefore, blocks representing objects in reference frames need not be repeated in adjacent frames. Specifically, an object such as a table can remain in a fixed position over multiple frames. Thus, the table can be written once and adjacent frames can reference the reference frame. A pattern matching mechanism may be employed to match objects across multiple frames. Additionally, moving objects may be represented over multiple frames, for example, due to object motion or camera motion. As a particular example, a video may show a car moving across a screen over multiple frames. Motion vectors may be employed to describe such motion. A motion vector is a two-dimensional vector that provides an offset from an object's coordinates in a frame to the object's coordinates in a reference frame. Thus, inter-prediction can encode image blocks in the current frame as a set of motion vectors that indicate offsets from corresponding blocks in the reference frame.

Intra prediction encodes blocks within a common frame. Intra prediction takes advantage of the fact that luminance and chroma components tend to be concentrated in frames. For example, green patches in a portion of a tree tend to be located adjacent to similar green patches. Intra prediction employs multi-prediction modes (eg, 33 in HEVC), planar mode, and direct current (DC) mode. The direction mode indicates that the current block is similar/same as the neighboring block's samples in the corresponding direction. Planar mode indicates that a series of blocks (eg, planes) along a row/column can be interpolated based on neighboring blocks at the ends of the rows. The planar mode effectively exhibits a smooth transition of light/color across rows/columns by adopting a relatively constant slope in changing values. DC mode is used for boundary smoothing and indicates that a block is similar/same as the average value associated with the samples of all neighboring blocks associated with the angular direction of the directional prediction mode. Thus, an intra-predicted block can represent an image block as various related prediction mode values instead of actual values. Additionally, inter-predicted blocks can represent image blocks as motion vector values instead of actual values. In either case, the predictive block may not be an exact representation of the image block in some cases. Any differences are stored in the residual block. A transform may be applied to the residual block to further compress the file.

Various filtering techniques may be applied in step 107 . In HEVC, filters are applied according to an in-loop filtering scheme. The block-based prediction discussed above may result in the generation of blocky images at the decoder. In addition, block-based prediction schemes may encode blocks and then reconstruct the encoded blocks for later use as reference blocks. An in-loop filtering scheme iteratively applies a noise suppression filter, a deblocking filter, an adaptive loop filter, and a sample adaptive offset (SAO) filter to blocks/frames. These filters mitigate such blocking artifacts so that the encoded file can be reconstructed accurately. Additionally, these filters mitigate artifacts in the reconstructed reference block, which are less likely to produce additional artifacts in subsequent blocks that are encoded based on the reconstructed reference block. .

Once the video signal has been split, compressed and filtered, the resulting data is encoded into a bitstream at step 109 . The bitstream includes the data discussed above and any signaling data desired to support proper video signal reconstruction at the decoder. For example, such data may include partition data, prediction data, residual blocks, and various flags that provide coding instructions to the decoder. The bitstream may be stored in memory for transmission towards the decoder upon request. The bitstream may also be broadcast and/or multicast to multiple decoders. Bitstream generation is an iterative process. Accordingly, steps 101, 103, 105, 107, and 109 may occur serially and/or simultaneously over many frames and blocks. The order shown in FIG. 1 is presented for clarity and ease of discussion and is not intended to limit the video coding process to any particular order.

The decoder receives the bitstream and begins the decoding process at step 111 . Specifically, the decoder employs an entropy decoding scheme that transforms the bitstream into corresponding syntax and video data. The decoder employs syntactic data from the bitstream to determine partitions for the frame at step 111 . The partitioning should match the result of block partitioning in step 103 . The entropy encoding/decoding employed in step 111 is now described. The encoder makes many choices during the compression process, such as choosing a block partitioning scheme from several possible choices based on the spatial positioning of values in the input image. Strict choice signaling may be employed by multiple bins. As used herein, bins are binary values that are treated as variables (eg, bit values that can vary depending on context). Entropy coding allows the encoder to leave a set of acceptable options and discard any options that are clearly not viable in the particular case. Each acceptable option is assigned a codeword. The codeword length is based on the number of allowable options (e.g., 1 bin for 2 options, 2 bins for 3-4 options, etc.), and the encoder then: , encode the codewords for the selected options. The scheme desirably indicates that the codeword uniquely indicates a choice from a small subset of the allowable options, as opposed to a choice from a potentially large set of all possible options. is so large that the size of the codeword is reduced. The decoder then decodes the selection by determining the set of allowable options in the same manner as the encoder. By determining the set of allowable options, the decoder can read the codeword and determine the choices made by the encoder.

At step 113, the decoder performs block decoding. Specifically, the decoder employs an inverse transform to generate the residual block. The decoder then employs the residual block and the corresponding prediction block to reconstruct the image block according to the partition. Predicted blocks may include both intra-predicted blocks and inter-predicted blocks, as generated at the encoder in step 105 . The reconstructed image blocks are then positioned within the frame of the reconstructed video signal according to the segmentation data determined in step 111 . The syntax for step 113 may also be signaled within the bitstream via entropy coding as discussed above.

At step 115 filtering is performed on the frames of the reconstructed video signal in a manner similar to step 107 in the encoder. For example, noise suppression filters, deblocking filters, adaptive loop filters, and SAO filters may be applied to the frames to remove blocking artifacts. Once the frames have been filtered, the video signal is output to a display in step 117 and can be viewed by the end user.

FIG. 2 is a schematic diagram of an exemplary coding and decoding (codec) system 200 for video coding. Specifically, codec system 200 provides functionality to support implementation of method of operation 100 . Codec system 200 is generalized to show the components employed in both the encoder and decoder. Codec system 200 receives and splits a video signal, as discussed with respect to steps 101 and 103 of method of operation 100 , resulting in split video signal 201 . Codec system 200 then compresses split video signal 201 into a coded bitstream when acting as an encoder, as discussed with respect to steps 105 , 107 and 109 of method 100 . When acting as a decoder, codec system 200 produces an output video signal from the bitstream as discussed with respect to steps 111 , 113 , 115 and 117 of method of operation 100 . Codec system 200 includes general coder control component 211, transform scaling and quantization component 213, intra picture estimation component 215, intra picture prediction component 217, motion compensation component 219, motion estimation component 221, scaling and inverse It includes a transform component 229 , a filter control analysis component 227 , an in-loop filter component 225 , a decoded picture buffer component 223 , a header formatting and context adaptive binary arithmetic coding (CABAC) component 231 . Such components are coupled as shown. In FIG. 2, black lines indicate movement of data to be encoded/decoded, and dashed lines indicate movement of control data that controls the operation of other components. All of the components of codec system 200 may reside within the encoder. A decoder may include a subset of the components of codec system 200 . For example, the decoder may include an intra-picture prediction component 217, a motion compensation component 219, a scaling and inverse transform component 229, an in-loop filter component 225, and a decoded picture buffer component 223. These constituent elements will now be described.

A segmented video signal 201 is a captured video sequence that has been segmented into blocks of pixels by a coding tree. Coding trees employ various split modes to divide blocks of pixels into smaller blocks of pixels. These blocks can then be further divided into smaller blocks. Blocks are sometimes referred to as nodes on the coding tree. Large parent nodes are split into smaller child nodes. The number of times a node is split further is called the depth of the node/coding tree. In some cases, the partitioned blocks can be included in coding units (CUs). For example, a CU may be a sub-portion of a CTU that includes luma blocks, red-difference chroma (Cr) locks, and blue-difference chroma (Cb) blocks, along with corresponding CU syntax instructions. The split mode is binary tree (BT), triple tree (TT ), and quadtree (QT). Split video signal 201 is subjected to general coder control component 211, transform scaling and quantization component 213, intra picture estimation component 215, filter control analysis component 227, and motion estimation component 221 for compression. transferred.

General coder control component 211 is configured to make decisions related to coding images of a video sequence into a bitstream according to application constraints. For example, the general coder control component 211 manages optimization of bitrate/bitstream size versus reconstruction quality. Such decisions may be made based on storage/bandwidth availability and image resolution requirements. The general coder control component 211 also manages buffer utilization relative to transmission rate to mitigate buffer underrun and overrun problems. To manage these issues, general coder control component 211 manages segmentation, prediction, and filtering by other components. For example, the general coder control component 211 can dynamically increase resolution and increase compression complexity to increase bandwidth usage, or decrease resolution and bandwidth usage. compression complexity can be reduced. Accordingly, general coder control component 211 controls other components of codec system 200 to balance bit rate concerns and video signal reconstruction quality. General coder control component 211 generates control data that controls the operation of other components. Control data is also forwarded to the header formatting and CABAC component 231 which is encoded in the bitstream into signal parameters for decoding at the decoder.

Split video signal 201 is also sent to motion estimation component 221 and motion compensation component 219 for inter prediction. A frame or slice of the partitioned video signal 201 may be partitioned into multiple video blocks. Motion estimation component 221 and motion compensation component 219 perform inter-predictive coding of received video blocks relative to one or more blocks in one or more reference frames to provide temporal prediction. . Codec system 200 may perform multiple coding passes, eg, to select an appropriate coding mode for each block of video data.

Motion estimation component 221 and motion compensation component 219 may be highly integrated, but are illustrated separately for conceptual purposes. Motion estimation, performed by motion estimation component 221, is the process of generating motion vectors, which estimate the motion of video blocks. A motion vector may indicate, for example, the displacement of the coded object relative to the predictive block. A predictive block is a block that is found to closely match the block being coded in terms of pixel differences. A prediction block may also be referred to as a reference block. Such pixel differences may be determined by summing absolute differences (SAD), sum of squared differences (SSD), or other difference metrics. HEVC employs several coded objects including CTU, Coding Tree Block (CTB), and CU. For example, a CTU can be split into CTBs, and a CTB can be split into CBs for inclusion in a CU. A CU may be encoded as a prediction unit (PU), which contains prediction data, and/or a transform unit (TU), which contains transform residual data for the CU. The motion estimation component 221 uses rate-distortion analysis as part of the rate-distortion optimization process to generate motion vectors, PUs and TUs. For example, the motion estimation component 221 may determine multiple reference blocks, multiple motion vectors, etc. for the current block/frame, and select the reference block, motion vector, etc. that has the best rate-distortion characteristics. You may The best rate-distortion performance balances both video reconstruction quality (eg, amount of data loss due to compression) and coding efficiency (eg, size of final encoding).

In some examples, codec system 200 may calculate values for sub-integer pixel positions of reference pictures stored in decoded picture buffer component 223 . For example, video codec system 200 may interpolate values at quarter-pixel positions, eighth-pixel positions, or other pixel sub-positions of a reference picture. Accordingly, the motion estimation component 221 may perform motion searches on full and fractional pixel positions and output motion vectors with fractional pixel accuracy. Motion estimation component 221 computes motion vectors for PUs of video blocks in inter-coded slices by comparing the positions of the PUs to the positions of predictive blocks in reference pictures. The motion estimation component 221 outputs the calculated motion vectors as header formatting and motion data to the CABAC component 231 for encoding and the motion to the motion compensation component 219 .

Motion compensation performed by motion compensation component 219 may involve fetching or generating a predictive block based on the motion vector determined by motion estimation component 221 . Also, in some examples, motion estimation component 221 and motion compensation component 219 may be functionally integrated. Upon receiving a motion vector for the PU of the current video block, motion compensation component 219 may locate the predictive block to which the motion vector points. A residual video block is then formed by subtracting the pixel values of the prediction block from the pixel values of the current video block being coded to form pixel difference values. In general, the motion estimation component 221 performs motion estimation for the luminance component and the motion compensation component 219 uses motion vectors calculated based on the luminance component for both the chroma and luminance components. The prediction and residual blocks are forwarded to transform scaling and quantization component 213 .

Split video signal 201 is also sent to intra-picture estimation component 215 and intra-picture prediction component 217 . Like motion estimation component 221 and motion compensation component 219, intra-picture estimation component 215 and intra-picture prediction component 217 may be highly integrated, but are illustrated separately for conceptual purposes. ing. Intra-picture estimation component 215 and intra-picture prediction component 217, as described above, instead of inter-prediction performed by inter-frame motion estimation component 221 and motion compensation component 219, Intra predict the current block. In particular, intra picture estimation component 215 determines the intra prediction mode to use for encoding the current block. In some examples, intra-picture estimation component 215 selects an appropriate intra-prediction mode for encoding the current block from multiple tested intra-picture prediction modes. The selected intra-prediction mode is then forwarded to header formatting and CABAC component 231 for encoding.

For example, intra picture estimation component 215 computes rate-distortion values using rate-distortion analysis for various tested intra-prediction modes, and selects the intra-prediction mode having the best rate-distortion characteristics among the tested modes. select. Rate-distortion analysis is generally used to generate the coded block, the amount of distortion (or error) between the coded block and the original non-coded block that was coded to generate the coded block, and the Determines the bitrate (eg, number of bits) to be used. The intra-picture estimation component 215 computes ratios from the distortion and rate for various encoded blocks to determine which intra-prediction mode exhibits the best rate-distortion value for the block. Additionally, the intra-picture estimation component 215 may be configured to code the depth blocks of the depth map using a depth modeling mode (DMM) based rate-distortion optimization (RDO). .

Intra-picture prediction component 217 generates a residual block from the predicted block based on a selected intra-prediction mode determined by intra-picture estimation component 215 when implemented at the encoder or at the decoder. may read the residual block from the bitstream when implemented in The residual block contains the difference in values between the prediction block and the original block represented as a matrix. The residual block is then forwarded to transform scaling and quantization component 213 . Intra-picture estimation component 215 and intra-picture prediction component 217 may operate on both the luminance and chroma components.

Transform scaling and quantization component 213 is configured to further compress the residual block. Transform scaling and quantization component 213 applies a transform, such as a discrete cosine transform (DCT), a discrete sine transform (DST), or conceptually similar transforms, to the residual block to produce video blocks containing residual transform coefficient values. to generate Wavelet transforms, integer transforms, subband transforms, or other types of transforms can also be used. A transform may transform the residual information from the pixel value domain to a transform domain, eg, the frequency domain. Transform scaling and quantization component 213 is also configured to scale the transformed residual information, eg, based on frequency. Such scaling involves applying a scale factor to the residual information such that different frequency information is quantized at different granularities, which affects the final visual quality of the reconstructed video. may affect Transform scaling and quantization component 213 is also configured to quantize the transform coefficients to further reduce bitrate. The quantization process may reduce the bit depth associated with some or all of the coefficients. The degree of quantization may be modified by adjusting the quantization parameter. In some examples, transform scaling and quantization component 213 may then perform a scan of the matrix containing the quantized transform coefficients. The quantized transform coefficients are forwarded to the header formatting and CABAC component 231 and encoded in the bitstream.

A scaling and inverse transform component 229 applies the inverse operation of the transform scaling and quantizing component 213 to support motion estimation. A scaling and inverse transform component 229 applies inverse scaling, transform, and/or quantization to reconstruct the residual block in the pixel domain, e.g., a reference block that may later become the predictive block for another current block. Use as Motion estimation component 221 and/or motion compensation component 219 may calculate reference blocks by adding residual blocks to corresponding prediction blocks for use in motion estimation of subsequent blocks/frames. . A filter is applied to the reconstructed reference block to mitigate artifacts produced during scaling, quantization, and transform. Such artifacts would otherwise cause inaccurate predictions (generate additional artifacts) when subsequent blocks are predicted.

Filter control analysis component 227 and in-loop filter component 225 apply filters to the residual block and/or the reconstructed image block. For example, the transformed residual blocks from the scaling and inverse transform component 229 are combined with the corresponding prediction blocks from the intra-picture prediction component 217 and/or the motion compensation component 219 to reconstruct the original image block. You may The filter may then be applied to the reconstructed image blocks. In some examples, the filter may be applied to the residual block instead. Like the other components in FIG. 2, the filter control analysis component 227 and the in-loop filter component 225 are highly integrated and may be implemented together, but for conceptual purposes they are separated. shown in The filters applied to the reconstructed reference blocks are applied to specific spatial regions and contain multiple parameters to adjust how such filters are applied. Filter control analysis component 227 analyzes the reconstructed reference block to determine where such filters should be applied and sets the corresponding parameters. Such data is forwarded to the header formatting and CABAC component 231 as filter control data for encoding. In-loop filter component 225 applies such filters based on filter control data. The filters may include deblocking filters, noise suppression filters, SAO filters, and adaptive loop filters. Such filters may be applied in the spatial/pixel domain (eg, reconstructed pixel blocks) or the frequency domain, depending on the example.

When operating as an encoder, the filtered and reconstructed image blocks, residual blocks, and/or prediction blocks are stored in a decoded picture buffer configuration for subsequent use in motion estimation as discussed above. Stored in element 223 . When operating as a decoder, the decoded picture buffer component 223 stores and forwards the reconstructed filtered blocks towards the display as part of the output video signal. Decoded picture buffer component 223 may be any memory device capable of storing prediction blocks, residual blocks, and/or reconstructed image blocks.

Header formatting and CABAC component 231 receives data from various components of codec system 200 and encodes such data into a coded bitstream for transmission towards the decoder. Specifically, the header formatting and CABAC component 231 generates various headers for encoding control data such as general control data and filter control data. Furthermore, prediction data, including intra-prediction and motion data, and residual data in the form of quantized transform coefficient data are all encoded into the bitstream. The final bitstream contains all the information desired by the decoder to reconstruct the original split video signal 201 . Such information also includes intra-prediction mode index tables (also called codeword mapping tables), definitions of coding contexts for various blocks, indications of most probable intra-prediction modes, indications of partition information, etc. It's okay. Such data may be encoded by employing entropy coding. For example, the information is encoded by using context-adaptive variable-length coding (CAVLC), CABAC, syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioned entropy coding (PIPE), or another entropy coding technique. may Following entropy coding, the coded bitstream may be sent to another device (eg, a video decoder), or archived for later transmission or retrieval.

FIG. 3 is a block diagram illustrating an exemplary video encoder 300. As shown in FIG. Video encoder 300 may be employed to implement the encoding functions of codec system 200 and/or to implement steps 101 , 103 , 105 , 107 and/or 109 of method of operation 100 . Encoder 300 splits an input video signal resulting in split video signal 301 , which is substantially similar to split video signal 201 . The split video signal 301 is then compressed and encoded into a bitstream by the encoder 300 components.

Specifically, split video signal 301 is forwarded to intra picture prediction component 317 for intra prediction. Intra-picture prediction component 317 may be substantially similar to intra-picture estimation component 215 and intra-picture prediction component 217 . Split video signal 301 is also forwarded to motion compensation component 321 for inter prediction based on reference blocks in decoded picture buffer component 323 . Motion compensation component 321 may be substantially similar to motion estimation component 221 and motion compensation component 219 . The prediction and residual blocks from intra-picture prediction component 317 and motion compensation component 321 are forwarded to transform and quantization component 313 for transform and quantization of the residual block. Transform and quantization component 313 may be substantially similar to transform scaling and quantization component 213 . The transformed and quantized residual block and corresponding prediction block (along with associated control data) are forwarded to entropy coding component 331 for coding into a bitstream. Entropy coding component 331 may be substantially similar to header formatting and CABAC component 231 .

The transformed and quantized residual blocks and/or corresponding prediction blocks are also inverse transformed and quantized from transform and quantization component 313 for reconstruction into reference blocks used by motion compensation component 321. Forwarded to component 329 . Inverse transform and quantization component 329 may be substantially similar to scaling and inverse transform component 229 . The in-loop filter in in-loop filter component 325 is also applied to the residual block and/or the reconstructed reference block, depending on the example. In-loop filter component 325 may be substantially similar to filter control analysis component 227 and in-loop filter component 225 . In-loop filter component 325 may include multiple filters, as discussed with respect to in-loop filter component 225 . The filtered blocks are then stored in the decoded picture buffer component 323 to be used as reference blocks by the motion compensation component 321. It may be substantially similar to component 223 .

FIG. 4 is a block diagram illustrating an exemplary video decoder 400. As shown in FIG. Video decoder 400 may be employed to implement the decoding functions of codec system 200 and/or to implement steps 111 , 113 , 115 and/or 117 of method of operation 100 . Decoder 400 receives the bitstream, eg, from encoder 300, and produces a reconstructed output video signal based on the bitstream for display to an end user.

The bitstream is received by entropy decoding component 433 . Entropy decoding component 433 is configured to implement an entropy decoding scheme such as CAVLC, CABAC, SBAC, PIPE coding, or other entropy coding techniques. For example, entropy decoding component 433 may employ header information to provide context for interpreting additional data encoded as codewords in the bitstream. The decoded information may include any desired information for decoding the video signal, such as general control data, filter control data, partition information, motion data, prediction data, and quantized transform coefficients from residual blocks. include. The quantized transform coefficients are forwarded to the inverse transform and quantization component 429 for reconstruction into residual blocks. Inverse transform and quantization component 429 may be similar to inverse transform and quantization component 329 .

The reconstructed residual and/or prediction blocks are forwarded to intra picture prediction component 417 for reconstruction into image blocks based on intra prediction operations. Intra-picture prediction component 417 may be similar to intra-picture estimation component 215 and intra-picture prediction component 217 . Specifically, the intra-picture prediction component 417 employs prediction modes to locate reference blocks within frames and applies residual blocks to the results to reconstruct intra-predicted image blocks. The reconstructed intra-predicted image blocks and/or residual blocks and corresponding inter-predicted data are forwarded to the decoded picture buffer component 423 via the in-loop filter component 425, which is the decoded They may be substantially similar to picture buffer component 223 and in-loop filter component 225, respectively. In-loop filter component 425 filters reconstructed image blocks, residual blocks and/or prediction blocks, and such information is stored in decoded picture buffer component 423 . Reconstructed image blocks from the decoded picture buffer component 423 are forwarded to the motion compensation component 421 for inter prediction. Motion compensation component 421 may be substantially similar to motion estimation component 221 and/or motion compensation component 219 . Specifically, motion compensation component 421 employs motion vectors from reference blocks to generate prediction blocks, and applies residual blocks to the results to reconstruct image blocks. The resulting reconstructed block may be forwarded to the decoded picture buffer component 423 via an in-loop filter component 425 . The decoded picture buffer component 423 continues to store additional reconstructed image blocks that can be reconstructed into frames via partition information. Such frames may be placed in a sequence. This sequence is output to the display as a reconstructed output video signal.

FIG. 5 is an example of a point cloud medium 500 that can be encoded according to the PCC scheme. A point cloud is a set of data points in space. A point cloud may be generated by a 3D scanner that measures a large number of points on the outer surface of the surrounding object. A point cloud may be described in terms of geometric attributes, texture attributes, reflectance attributes, transparency attributes, normal attributes, and the like. Each attribute may be encoded by a codec, such as video codec system 200 , encoder 300 and/or decoder 400 as part of method 100 . Specifically, each attribute of the PCC frame can be separately coded at the encoder, decoded at the decoder, and recombined to recreate the PCC frame.

Point cloud medium 500 includes three bounding boxes 502 , 504 , and 506 . Each of bounding boxes 502, 504, and 506 represents a portion or segment of the 3D image from the current frame. Bounding boxes 502, 504, and 506 include 3D images of people, but other objects may be included in the bounding boxes in practical applications. Each bounding box 502, 504, and 506 includes x, y, and z axes that indicate the number of pixels occupied by the 3D image in the x, y, and z directions, respectively. For example, the x-axis and y-axis represent approximately 400 pixels (eg, approximately 0-400 pixels) and the z-axis represents approximately 1000 pixels (eg, approximately 0-1000 pixels).

Each of bounding boxes 502, 504, and 506 contains one or more patches 508 represented by the cubes or boxes in FIG. Each patch 508 includes a portion of the entire object within one of bounding boxes 502, 504, or 506 and may be described or represented by patch size information. Patch information may include, for example, two-dimensional (2D) and/or three-dimensional (3D) coordinates that describe the location of patch 508 within bounding box 502 , 504 , or 506 . Patch information may also include other parameters. For example, patch information may include parameters such as normalAxis that are inherited from the reference patch information to the current patch information. That is, one or more parameters from the patch information of the reference frame may be inherited for the patch information of the current frame. Additionally, one or more metadata portions (eg, patch rotation, scale parameters, material identifiers, etc.) from the reference frame may be inherited to the current frame. Patches 508 are sometimes referred to interchangeably herein as 3D patches or patch data units. A list of patches 508 within each bounding box 502, 504, or 506 may be generated and stored in the patch buffer in descending order from largest patch to smallest patch. This patch can then be encoded by an encoder and/or decoded by a decoder.

Patches 508 may describe various attributes of point cloud media 500 . Specifically, the position of each pixel on the x-, y-, and z-axes is the geometry of that pixel. A patch 508 containing the positions of all pixels in the current frame can be coded to capture the geometric attributes for the current frame of the point cloud medium 500 . Additionally, each pixel may include color values in the red, blue, and green (RGB) and/or luminance and saturation (YUV) spectrum. A patch 508 containing the colors of all pixels in the current frame can be coded to capture texture attributes for the current frame of the point cloud medium 500 .

Additionally, each pixel may (or may not) contain some reflectance. Reflectance is the amount of light (eg, colored light) that a pixel projects onto neighboring pixels. Shining objects have a high reflectance, thus spreading the light/color of their corresponding pixels to other nearby pixels. Matte objects, on the other hand, have little or no reflectance and may not affect the color/light levels of neighboring pixels. A patch 508 containing the reflectance of all pixels in the current frame can be coded to capture the reflectance attributes for the current frame of the point cloud medium 500 . Some pixels may be partially or completely transparent (eg, glass, clear plastic, etc.). Transparency is the amount of adjacent pixel light/color that can pass through the current pixel. A patch 508 containing the transparency levels of all pixels in the current frame can be coded to capture the transparency attribute for the current frame of the point cloud medium 500 . Additionally, the points of the point cloud medium may generate a surface. A surface can be associated with a normal vector, which is a vector perpendicular to the surface. Normal vectors can be useful when describing object motion and/or interactions. Therefore, in some cases, users may wish to encode normal vectors for surfaces to support additional functionality. A patch 508 containing normal vectors to surfaces in the current frame can be coded to capture normal attributes for the current frame of the point cloud medium 500 .

Geometry, texture, reflectance, transparency, and normal attributes may include data describing some or all data points within the point cloud medium 500, depending on the example. For example, the reflectance, transparency, and normal attributes are optional, and thus occur individually or in combination in some point cloud media 500 examples and not in others, even in the same bitstream. Sometimes. Thus, the number of patches 508, and thus the number of attributes, may vary from frame to frame and video to video based on filmed subject matter, video settings, and the like.

FIG. 6 is an example of data segmentation and packing for a point cloud media frame 600. FIG. Specifically, the example of FIG. 6 shows a 2D representation of patch 508 of point cloud medium 500 . A point cloud media frame 600 includes a bounding box 602 corresponding to the current frame from the video sequence. Bounding box 602 is 2D, in contrast to bounding boxes 502, 504, and 506 of FIG. 5, which are 3D. As shown, bounding box 602 includes multiple patches 604 . Patches 604 are sometimes referred to interchangeably herein as 2D patches or patch data units. Collectively, patch 604 in FIG. 6 is a representation of the image within bounding box 504 in FIG. Thus, the 3D image within bounding box 504 of FIG. 5 is projected onto bounding box 602 through patch 604 . Portions of bounding box 602 that do not contain one of patches 604 are referred to as voids 606 . Void 606 may also be referred to as a void, empty sample, or the like.

With the above in mind, video-based point cloud compression (PCC) codec solutions are based on segmenting 3D point cloud data (e.g., patch 508 in FIG. 5) into 2D projection patches (e.g., patch 604 in FIG. 6). Please note that Indeed, the coding method or process described above can be used, for example, in immersive six degrees of freedom (6 DoF), dynamic augmented/virtual reality (AR/VR) objects, cultural heritage, graphic information systems (GIS), computer aided design ( CAD), autonomous navigation, etc. may be beneficially implemented.

The position of each patch (eg, one of patches 604 in FIG. 6) within a bounding box (eg, bounding box 602) may be determined solely by the size of the patch. For example, the largest of patches 604 in FIG. 6 is first projected onto bounding box 602 starting at the upper left corner (0,0). After the largest of patches 604 is projected onto bounding box 602 , the next largest patch 604 is projected (aka filled) onto bounding box 602 and the smallest of patches 604 is projected onto bounding box 602 . Continues until projected upwards. Again, only the size of each patch 604 is considered in this process. In some cases, patches 604 with smaller sizes may occupy more space between patches and will have a position closer to the upper left corner of bounding box 602 than larger patches 604 . During encoding, this process may be repeated for each relevant attribute until a patch for each attribute in the frame is encoded into one or more corresponding attribute streams. Groups of data units within the attribute stream that are used to recreate a single frame can then be stored in a bitstream within the PCC AU. At the decoder, these attribute streams are obtained from the PCC AU and decoded to produce patches 604 . Such patches 604 can then be combined to recreate the PCC media. Thus, the point-cloud media frames 600 can be processed by video codec system 200, encoder 300, and/or decoder 400, as part of method 100 for compressing point-cloud media 500 for transmission. It can be encoded by a codec.

FIG. 7 is a schematic diagram illustrating an exemplary PCC video stream 700 with an extended attribute set. For example, PCC video stream 700 is encoded according to method 100 by point-cloud media frames 600 from point-cloud media 500, eg, by employing video codec system 200, encoder 300, and/or decoder 400. may be generated when

PCC video stream 700 includes a sequence of PCC AUs 710 . PCC AU 710 contains enough data to reconstruct a single PCC frame. Data is placed in the PCC AU 710 within the NAL unit 720 . NAL unit 720 is a packet-sized data container. For example, a single NAL unit 720 is generally sized to allow simple network transmission. NAL unit 720 may include a header that indicates the type of NAL unit 720 and a payload that includes associated video data. The PCC video stream 700 is designed for extended attribute sets and therefore contains several attribute-specific NAL units 720 .

The PCC video stream 700 includes a group of frames (GOF) header 721, ancillary information frames 722, an occupancy map frame 723, a geometry NAL unit 724, a texture NAL unit 725, a reflection NAL unit 726, a transparency NAL unit 727, and a normal NAL units 728 , each of which is a type of NAL unit 720 . The GOF header 721 includes various syntactical elements that describe the corresponding PCC AU 710 , the frames associated with the corresponding PCC AU 710 , and/or other NAL units 720 within the PCC AU 710 . PCC AU 710 may include a single GOF header 721 or no GOF header 721, depending on the example. Auxiliary information frame 722 may contain metadata associated with the frame, such as information associated with the patch used to encode attributes. The occupancy map frame 723 may include further metadata associated with the frame, such as an occupancy map that indicates areas of frames that are empty versus areas of frames that are occupied with data. The remaining NAL units 720 contain attribute data for the PCC AU 710 . Specifically, geometry NAL unit 724, texture NAL unit 725, reflection NAL unit 726, transparency NAL unit 727, and normal NAL unit 728 are used to define geometric, texture, reflection, and transmission attributes, respectively. attributes, and normal attributes.

As noted above, attributes can be organized into streams. For example, there may be 0-4 streams for each attribute. A stream may contain logically separate portions of PCC video data. For example, attributes for different objects may be represented by multiple attribute streams of the same type (e.g., a first geometry stream for a first 3D bounding box, a second attribute stream). In another example, attributes associated with different frames may be encoded into multiple attribute streams (eg, a transparency attribute stream for even frames, a transparency attribute stream for odd frames). In yet another example, patches may be layered to represent a 3D object. Thus, separate layers may be included in separate streams (eg, a first texture attribute stream for the top layer, a second texture attribute stream for the second layer, etc.). Regardless of the example, the PCC AU 710 may contain 0, 1 or more NAL units for the corresponding attributes.

This disclosure codes various attributes (eg, as included in geometry NAL unit 724, texture NAL unit 725, reflection NAL unit 726, transparency NAL unit 727, and/or normal NAL unit 728). support increased flexibility for In a first example, different codecs can be employed to code different PCC attributes. As a specific example, a first codec can be employed to encode the geometry of the PCC video into the geometry NAL unit 724, and a second codec can be employed to encode the reflections of the PCC video. Encode into reflection NAL unit 726 . As another example, when coding PCC video, up to five codecs (eg, one codec for each attribute) may be employed. The codec used for the attribute can then be signaled as a syntax element in the PCC video stream 700, eg, GOF header 721.

Further, as noted above, PCC attributes may employ many combinations of layers and/or streams. Therefore, each attribute is encoded using a syntax element (eg, in the GOF header 721) to allow the decoder to determine the layer and/or stream combination for each attribute when decoding. The layer and/or stream combination used by the encoder when encoding can be signaled. Additionally, syntax elements (eg, in the GOF header 721) can be used to signal the mode used to code and/or combine layers of PCC attributes within the PCC attribute stream. Additionally, a syntax element (eg, in the GOF header 721) can be used to specify the layer index of the layer associated with each NAL unit 720 corresponding to the PCC attribute stream. For example, the GOF header 721 is used to specify the number of layers and streams associated with geometric attributes, the manner in which such layers and streams are arranged, and the layer index for each geometric NAL unit 724. , so that the decoder can assign each geometric NAL unit 724 to the appropriate layer when decoding the PCC frame.

Finally, a flag (eg, in the GOF header 721) can indicate whether any PCC attribute layer contains any irregular point cloud points. An irregular point cloud is a set of one or more data points that are non-contiguous with neighboring data points and therefore cannot be represented by a 2D patch such as patch 604 . Instead, such points are represented as part of an irregular point cloud patch that includes coordinates and/or transformation parameters associated with such irregular point cloud points. Since the irregular point cloud is represented using a different data structure than the 2D patch, the flag enables the decoder to properly recognize the presence of an irregular point cloud and provide the appropriate mechanism for decoding such data. allow you to choose.

The following are exemplary mechanisms for implementing the aspects described above. Definition: A video NAL unit is a PCC NAL unit with PccNalUnitType equal to GMTRY_NALU, TEXTURE_NALU, REFLECT_NALU, TRANSP_NALU, or NORMAL_NALU.

Bitstream Format: This section specifies the relationship between the NAL unit stream and the byte stream, either called bitstream. A bitstream can be in one of two formats: NAL unit stream format or byte stream format. The NAL unit stream format is conceptually a more basic type, containing a set of syntactic structures called PCC NAL units. This sequence is ordered in decoding order. There are constraints imposed on the decoding order (and content) of PCC NAL units in the NAL unit stream. A byte stream format may be constructed from the NAL unit stream format by placing the NAL units in decoding order and prefixing each NAL unit with a start code prefix and zero or more zero value bytes to form a byte stream. The NAL unit stream format can be extracted from the byte stream format by searching for the position of the unique start code prefix pattern within this stream of bytes. The byte stream format is similar to that adopted by HEVC and AVC.

The PCC NAL unit header syntax may be implemented as set forth in Table 1 below.

The PCC profile and level syntax may be implemented as described in Table 3 below.

PCC NAL unit header semantics may be implemented as follows. forbidden_zero_bit may be set equal to zero. pcc_nal_unit_type_plus1-1 specifies the value of the variable PccNalUnitType, which specifies the type of RBSP data structure contained in the PCC NAL unit, as specified in Table 4 below. The variable NalUnitType is specified as follows:
PccNalUnitType=pcc_nal_unit_type_plus1-1 (7-1) PCC NAL units with nal_unit_type in the range UNSPEC25 to UNSPEC30 with unspecified semantics have no effect on the decoding process specified herein. Note that PCC NAL units in the range UNSPEC25 to UNSPEC30 may be used as determined by the application. The decoding process for these values of PccNalUnitType is not specified in this disclosure. Since different applications may use these PCC NAL unit types for different purposes, the design of encoders that generate PCC NAL units with these PccNalUnitType values and the content of PCC NAL units with these PccNalUnitType values Special attention should be paid to the design of decoders that interpret This disclosure does not define any control over these values. These PccNalUnitType values may only be suitable for use in contexts where usage conflicts (e.g., different definitions of the content of a PCC NAL unit for the same PccNalUnitType value) are immaterial and not possible; For example, defined or managed by a controlling application or transport specification, or by controlling the environment in which the bitstream is distributed.

For purposes other than determining the amount of data in the PCC AUs of the bitstream, the decoder shall ignore (remove from the bitstream and discard) the contents of all PCC NAL units that use the reserved value of PccNalUnitType. good too. This requirement may allow future definition of compatible extensions to this disclosure.

The identified video codec (eg, HEVC or AVC) is indicated in the group of frame header NAL units present in the first PCC AU of each cloud point stream (CPS). pcc_stream_id specifies the PCC stream identifier (ID) of the PCC NAL unit. The value of pcc_stream_id is set to zero when PccNalUnitType is equal to GOF_HEADER, AUX_INFO or OCP_MAP. The definition of one or more sets of PCC profiles and levels may constrain the value of pcc_stream_id to be less than four.

The order of PCC NAL units and their association to PCC AUs is described below. The PCC AU contains zero or one group of frame header NAL units, one auxiliary information frame NAL unit, one occupied map frame NAL unit, and PCC attributes such as geometry, texture, reflection, transparency, or normal. contains one or more video AUs carrying data units of video_au(i,j) denotes a video AU whose pcc_stream_id is equal to j for the PCC attribute whose PCC attribute ID is equal to attribute_type[i]. Video AUs present in the PCC AU may be ordered as follows. If attributes_first_ordering_flag is equal to 1, then for any two video AUs video_au(i1,j1) and video_au(i2,j2) present in the PCC AU, the following applies. If i1 is less than i2, video_au(i1,j1) shall precede video_au(i2,j2) regardless of the values of j1 and j2. Otherwise, if i1 is equal to i2 and j1 is greater than j2, then video_au(i1,j1) shall follow video_au(i2,j2).

Otherwise (eg attributes_first_ordering_flag equals 0), for the two video AUs video_au(i1,j1) and video_au(i2,j2) present in the PCC AU, the following applies. If j1 is less than j2, video_au(i1,j1) shall precede video_au(i2,j2) regardless of the values of i1 and i2. Otherwise, if j1 is equal to j2 and i1 is greater than i2, then video_au(i1,j1) shall follow video_au(i2,j2). The above order of video AUs yields: If attributes_first_ordering_flag is equal to 1, then the order of the video AUs, if any, within the PCC AU is as follows (in the order listed). Here, within the PCC AU, all PCC NAL units of each PCC attribute, if any, are contiguous in decoding order without being interleaved with PCC NAL units of other PCC attributes. That is, video_au(0,0), video_au(0,1), . . . , video_au(0, num_streams_for_attribute[0]), video_au(1,0), video_au(1,1), . . . , video_au(1, num_streams_for_attribute[1]), video_au(num_attributes-1,0), video_au(num_attributes-1,1), . . . , video_au(num_attributes−1, num_streams_for_attribute[1]). Otherwise (attributes_first_ordering_flag equals 0), the order of the video AUs, if any, within the PCC AU is as follows (in the order listed), and within the PCC AU all for each specific pcc_stream_id value , if present, are contiguous in decoding order without being interleaved with PCC NAL units of other pcc_stream_id values. That is, video_au(0,0), video_au(1,0), . . . , video_au(num_attributes-1,0), video_au(0,1), video_au(1,1), . . . , video_au(num_attributes−1, 1), video_au(0, num_streams_for_attribute[1]), video_au(1, num_streams_for_attribute[1]), . . . , video_au(num_attributes−1, num_streams_for_attribute[1]).

The association of NAL units to video AUs and the ordering of NAL units within video AUs is specified in the specification of the identified video codec, eg, HEVC or AVC. The identified video codec is indicated in the Frame Header NAL unit present in the first PCC AU of each CPS.

The first PCC AU of each CPS starts with a group of frame header NAL units, and each group of frame header NAL units designates the start of a new PCC AU.

Other PCC AUs start with an auxiliary information frame NAL unit. In other words, an auxiliary information frame NAL unit starts a new PCC AU if it is not preceded by a group of frame header NAL units.

The semantics of a group of frame header RBSPs are as follows. num_attributes specifies the maximum number of PCC attributes (geometry, texture, etc.) that can be carried in the CPS. Note that the definition of one or more sets of PCC profiles and levels may constrain the value of num_attributes to 5 or less. attributes_first_ordering_flag, when equal to 0, within the PCC AU all PCC NAL units of each PCC attribute, if any, shall be contiguous in decoding order without being interleaved with PCC NAL units of other PCC attributes. Specify attributes_first_ordering_flag, when set equal to 0, within the PCC AU all PCC NAL units for each particular pcc_stream_id value are decoded without being interleaved, if any, with PCC NAL units for other pcc_stream_id values Specifies that they are consecutive in order. attribute_type[i] specifies the PCC attribute type of the i-th PCC attribute. The interpretation of different PCC attribute types is specified in Table 5 below. In defining one or more sets of PCC profiles and levels, the values of attribute_type[0] and attribute_type[1] may be constrained to equal 0 and 1, respectively.

identified_codec_for_attribute[i] specifies the identified video codec used for coding the i-th PCC attribute, as shown in Table 6 below.

num_streams_for_attribute[i] specifies the maximum number of PCC streams for the i-th PCC attribute. Note that the definition of one or more sets of PCC profiles and levels may constrain the value of num_streams_for_attribute[i] to 4 or less. num_layers_for_attribute[i] specifies the number of attribute layers for the i-th PCC attribute. Note that the definition of one or more sets of PCC profiles and levels may constrain the value of num_layer_for_attribute[i] to 4 or less. max_attribute_layer_idx[i][j] specifies the maximum attribute layer index of the PCC stream with pcc_stream_id equal to j for the i-th PCC attribute. The value of max_attribute_layer_idx[i][j] should be less than num_layer_for_attribute[i]. attribute_layers_combination_mode[i][j] specifies the attribute layer combination mode for attribute layers carried in PCC streams, with pcc_stream_id equal to j for the i-th PCC attribute. The interpretation of different values of attribute_layers_combination_mode[i][j] is specified in Table 7 below.

A variable attrLayerIdx[i][j] that indicates the attribute layer index for the attribute layer of the PCC stream with pcc_stream_id equal to j for the i-th PCC attribute when attribute_layers_combination_mode[i][j] is present and equal to 0 ], the attribute layer PCC NAL unit carried in the video AU with the picture order count value equal to PicOrderCntVal as specified in the identified video codec's specification is derived as follows.

regular_points_flag[i][j], if equal to 1, specifies that for the i-th PCC attribute the attribute layer carries regular points of the point cloud signal with layer index equal to j. regular_points_flag[i][j], if equal to 0, specifies that for the i-th PCC attribute the attribute layer carries the regular points of the point cloud signal with the layer index equal to j. Note that the definition of one or more sets of PCC profiles and levels may constrain the value of regular_points_flag[i][j] to zero. frame_width indicates the frame width of the geometry and texture video in pixels. The frame width should be a multiple of the occupancyResolution. frame_height indicates the frame height of the geometry and texture video in pixels. The frame height should be a multiple of the occupancyResoluton. occupancy_resolution indicates the horizontal and vertical resolution, in pixels, at which patches are packed into the geometry and texture video. The occupancy_resolution should be an even multiple of the occupancyPrecision. radius_to_smoothing indicates the radius for detecting neighbors for smoothing. The value of radius_to_smooting should be in the range 0-255.

neighbor_count_smooting indicates the maximum number of neighbors used for smoothing. The value of neighbor_count_smooting should be in the range 0-255. radius2_boundary_detection indicates the radius for boundary point detection. The value of radius2_boundary_detection should be in the range 0-255. threshold_smooting indicates the smoothing threshold. The value of threshold_smooting should be in the range 0-255. lossless_geometry indicates reversible geometry coding. The value of lossless_geometry, when equal to 1, indicates that the point cloud geometry information is losslessly encoded. The value of lossless_geometry, when equal to 0, indicates that the point cloud geometry information is coded losslessly. lossless_texture indicates lossless texture encoding. The value of lossless_texture, when equal to 1, indicates that the point cloud texture information is losslessly encoded. The value of lossless_texture, when equal to 0, indicates that the point cloud texture information is lossy encoded. lossless_geometry_444 indicates whether to use 4:2:0 or 4:4:4 video format for geometry frames. The value of lossless_geometry_444, when equal to 1, indicates that the geometry video is coded in 4:4:4 format. The value of lossless_geometry_444, when equal to 0, indicates that the geometry video is coded in 4:2:0 format.

absolute_d1_coding indicates how geometry layers other than the layer closest to the projection plane are coded. absolute_d1_coding, when equal to 1, indicates that the actual geometry value is coded for a geometry layer other than the layer closest to the projection plane. absolute_d1_coding, when equal to 0, indicates that geometry layers other than the layer closest to the projection plane are differentially coded. bin_agithmetic_coding indicates whether binary arithmetic coding is used. The value of bin_agithmetic_coding, when equal to 1, indicates that binary arithmetic coding is used for all syntax elements. The value of bin_agithmetic_coding, if equal to 0, indicates that non-binary arithmetic coding is used for some syntax elements. gof_header_extension_flag, when equal to 0, specifies that the gof_header_extension_data_flag syntax element is not present in the group of frame header RBSP syntax structures. gof_header_extension_flag, when equal to 1, specifies that the gof_header_extension_data_flag syntax element is present in the group of frame header RBSP syntax structures. The decoder may ignore all data following the gof_header_extension_flag value of 1 in a group of frame header NAL units. gof_header_extension_data_flag may have any value, and the presence and value of the flag does not affect decoder conformance. A decoder may ignore all gof_header_extension_data_flag syntax elements.

The PCC profile and level semantics are as follows. pcc_profile_idc indicates the profile to which the CPS conforms. pcc_pl_reserved_zero — 19bits is equal to 0 for bitstreams conforming to this version of this disclosure. Other values of pcc_pl_reserved_zero — 19bits are reserved for future use by ISO/IEC. A decoder may ignore the value of pcc_pl_reserved_zero — 19bits. pcc_level_idc indicates the level to which the CPS conforms. When an HEVC bitstream for a PCC attribute type equal to attribute_type[i] extracted as specified by the sub-bitstream extraction process is decoded by a compliant HEVC decoder, in an active SPS hevc_ptl_12bytes_attribute[i] is , general_profile_idc to general_level_idc, which may be equal to a 12-byte value. When an AVC bitstream for a PCC attribute type equal to attribute_type[i] extracted as specified by the sub-bitstream extraction process is decoded by a compliant AVC decoder, in an active SPS, avc_pl_3ytes_attribute[i] is May be equal to a 3-byte value from profile_idc to level_idc.

The sub-bitstream extraction process is as follows. The inputs to this process are the PCC bitstream inBitstream, the target PCC attribute type targetAttrType, and the target PCC stream ID value targetStreamId. The output of this process is a sub-bitstream. This section with a conforming PCC bitstream inBitstream, targetAttrType indicating any type of PCC attribute present in inBitstream, and targetStreamId less than or equal to the maximum PCC stream ID value of the PCC streams present in inBitstream for attribute type targetAttrType. Any output sub-bitstream that is the output of the process specified in shall be a video bitstream conforming per the identified video codec specification for the attribute type targetAttrType is the bitstream for the input bitstream It may be a conformance requirement.

The output sub-bitstream is derived by the following ordered steps. Depending on the value of targetAttrType the following applies: If targetAttrType equals ATTR_GEOMETRY, remove all PCC NAL units whose PccNalUnitType is not equal to GMTRY_NALU or whose pcc_stream_id is not equal to targetStreamId. Otherwise, if targetAttrType equals ATTR_TEXTURE, all PCC NAL units with PccNalUnitType not equal to TEXTURE_NALU or pcc_stream_id not equal to targetStreamId are deleted. Otherwise, if targetAttrType equals ATTR_REFLECT, all PCC NAL units with PccNalUnitType not equal to REFLECT_NALU or pcc_stream_id not equal to targetStreamId are deleted. Otherwise, if targetAttrType equals ATTR_TRANSP, all PCC NAL units with PccNalUnitType not equal to TRANSP_NALU or pcc_stream_id not equal to targetStreamId are deleted. Otherwise, if targetAttrType equals ATTR_NORMAL, all PCC NAL units with PccNalUnitType not equal to NORMAL_NALU or pcc_stream_id not equal to targetStreamId are deleted. For each PCC NAL unit, the first byte may be deleted.

In an alternative embodiment of the first set of methods summarized above, the PCC NAL unit header uses more bits for pcc_stream_id and allows more than four streams for each attribute. Designed. In that case, add one more type to the header of the PCC NAL unit.

FIG. 8 is a schematic diagram illustrating an exemplary mechanism 800 for encoding PCC attributes 841 and 842 with multiple codecs 843 and 844. FIG. For example, mechanism 800 may be employed to encode and/or decode attributes of PCC video stream 700 . Accordingly, mechanism 800 can be employed to encode and/or decode point cloud media frames 600 based on point cloud media 500 . Thus, mechanism 800 may be used by encoder 300 to generate a bitstream from a PCC sequence and by decoder 400 to reconstruct a PCC sequence from the bitstream. Thus, mechanism 800 can be employed by codec system 200 and may also be employed to support method 100 .

Mechanism 800 can be applied to multiple PCC attributes 841 and 842 . For example, PCC attributes 841 and 842 may be any two attributes selected from the group including geometry attributes, texture attributes, reflectance attributes, transparency attributes, and normal attributes. As shown in FIG. 8, mechanism 800 shows the encoding process when going from left to right and the decoding process when going from right to left. Codecs 843 and 844 may be any two codecs, such as HEVC, AVC, VVC, or any version thereof. Certain codecs 843 and 844, or versions thereof, may be more efficient than others when encoding certain PCC attributes 841 and 842. In this example, codec 843 is used to encode attribute 841 and codec 844 is used to encode attribute 842, respectively. The results of such encoding are combined to produce a PCC video stream 845 containing both PCC attributes 841 and 842 . At the decoder, codec 843 is used to decode attribute 841 and codec 844 is used to decode attribute 842, respectively. Decoded attributes 841 and 842 can then be recombined to produce decoded PCC video stream 845 .

An advantage of employing mechanism 800 is that the most efficient codecs 843 and 844 can be selected for corresponding attributes 841 and 842 . Mechanism 800 is not limited to two attributes 841 and 842 and two codecs 843 and 844 . For example, each attribute (geometry, texture, reflectance, transparency, and normal) can be encoded by a separate codec. To ensure that the appropriate codecs 843 and 844 can be selected to decode the corresponding attributes 841 and 842, the encoder assigns them to codecs 843 and 844 and attributes 841 and 842, respectively. may signal the response of For example, an encoder can include a syntax element in the GOF header to indicate the codec to attribute correspondence. The decoder can then read the relevant syntax, select the correct codecs 843 and 844 for the attributes 841 and 842 and decode the PCC video stream 845 . As a specific example, the identified_codec_for_attribute syntax element may be employed to indicate codecs 843 and 844 for attributes 841 and 842, respectively.

FIG. 9 is a schematic diagram 900 showing examples of attribute layers 931 , 932 , 933 , and 934 . For example, attribute layers 931 , 932 , 933 and 934 may be employed to carry attributes of PCC video stream 700 . Layers 931 , 932 , 933 and 934 may thus be used when encoding and/or decoding point cloud media frames 600 based on point cloud media 500 . Thus, layers 931, 932, 933, and 934 may be used by encoder 300 to generate a bitstream from the PCC sequence, and decoder 400 to reconstruct the PCC sequence from the bitstream. May be used when Thus, layers 931 , 932 , 933 and 934 may be employed by codec system 200 and may also be employed to support method 100 . Additionally, attribute layers 931 , 932 , 933 and 934 may be used to carry one or more of attributes 841 and 842 .

Attribute layers 931, 932, 933, and 934 are groupings of attribute-related data that can be stored and/or modified independently of other groups of data related to the same attribute. In this manner, each attribute layer 931, 932, 933, and 934 can be modified and/or represented without affecting the remaining attribute layers 931, 932, 933, and/or 934. In some examples, attribute layers 931, 932, 933, and/or 934 may be visually represented on top of each other, as shown in FIG. For example, textures covering an entire object (eg, more general) can be stored in attribute layer 931, and more detailed textures (eg, more specific) can be stored in attribute layers 932, 933, and/or included in 934. In another example, attribute layers 931 and/or 932 may be applied to odd numbered frames and attribute layers 933 and/or 934 may be applied to even numbered frames. This may allow some layers to be skipped in response to frame rate changes. Each attribute may have 0-4 attribute layers 931 , 932 , 933 and/or 934 . To signal the configuration to be adopted, the encoder may employ syntax elements such as num_layers_for_attribute[i] to sequence-level data such as GOF headers. A decoder can read the syntax elements and determine the number of attribute layers 931, 932, 933, and/or 934 employed for each attribute. Additional syntax elements, e.g., attribute_layers_combination_mode[i][j], attrLayerIdx[i][j], etc., are employed to specify the combination of attribute layers employed in the PCC video stream and the number of layers used by the corresponding attributes. Each index can also be indicated.

As yet another example, some attribute layers (eg, attribute layers 931, 932, and 933) may carry data about regular patches, while other attribute layers (eg, attribute layer 934) may carry data about regular patches. carries the data associated with irregular point cloud patches. This is useful because irregular point clouds may be explained using different data than regular cloud patches. To signal that a particular layer carries data associated with an irregular point cloud, the encoder can encode another syntax element in the sequence-level data. As a specific example, a regular_points_flag in the GOF header can be used to indicate that the attribute layer carries at least one regular point cloud point. A decoder can then read the syntax elements and decode the corresponding attribute layers accordingly.

FIG. 10 is a schematic diagram 1000 showing examples of attribute streams 1031 , 1032 , 1033 , and 1034 . For example, attribute streams 1031 , 1032 , 1033 and 1034 can be employed to carry attributes of PCC video stream 700 . Accordingly, attribute streams 1031 , 1032 , 1033 , and 1034 may be employed when encoding and/or decoding point cloud media frames 600 based on point cloud media 500 . Thus, attribute streams 1031, 1032, 1033, and 1034 are used by encoder 300 to create a bitstream from the PCC sequence and used by decoder 400 to reconstruct the PCC sequence from the bitstream. may be Accordingly, attribute streams 1031 , 1032 , 1033 and 1034 may be employed by codec system 200 and may also be employed to support method 100 . Additionally, attribute streams 1031 , 1032 , 1033 and 1034 may be used to carry one or more of attributes 841 and 842 . Additionally, attribute streams 1031 , 1032 , 1033 and 1034 may be employed to carry attribute layers 931 , 932 , 933 and 934 .

Attribute streams 1031, 1032, 1033, and 1034 are sequences of attribute data over time. Specifically, attribute streams 1031, 1032, 1033, and 1034 are substreams of the PCC video stream. Each attribute stream 1031, 1032, 1033, and 1034 carries a sequence of attribute-specific NAL units and thus acts as a storage and/or transmission data structure. Each attribute stream 1031, 1032, 1033, and 1034 may carry one or more attribute layers 931, 932, 933, and 934 of data. For example, attribute stream 1031 may carry attribute layers 931 and 932, while attribute stream 1032 carries attribute layers 931 and 932 (attribute streams 1033 and 1034 are omitted). In another example, each attribute stream 1031 , 1032 , 1033 and 1034 carries a single corresponding attribute layer 931 , 932 , 933 and 934 . In another example, some attribute streams 1031, 1032, 1033, and 1034 carry multiple attribute layers 931, 932, 933, and 934, while other attribute streams 1031, 1032, 1033, and 1034 , carry a single attribute layer 931, 932, 933, and 934, or be omitted. As can be seen, many combinations and permutations of attribute streams 1031, 1032, 1033 and 1034 and attribute layers 931, 932, 933 and 934 can occur. Therefore, the encoder uses syntax such as num_streams_for_attribute in sequence level data such as the GOF header to indicate the number of attribute streams 1031, 1032, 1033, and 1034 used to encode each attribute. element can be adopted. A decoder can then decode attribute streams 1031, 1032, 1033, and 1034 to reconstruct a PCC sequence using such information, eg, in combination with attribute layer information.

FIG. 11 is a flowchart of an exemplary method 1100 of encoding a PCC video sequence with multiple codecs. For example, method 1100 may organize data into bitstreams according to mechanism 800 while using attribute layers 931, 932, 933, and 934 and/or streams 1031, 1032, 1033, and/or 1034. . The method 1100 may also specify the mechanism used to encode attributes within the GOF header. Additionally, method 1100 may generate PCC video stream 700 by encoding point-cloud media frames 600 based on point-cloud media 500 . Additionally, method 1100 may be employed by codec system 200 and/or encoder 300 while performing the encoding steps of method 100 .

Method 1100 may begin when an encoder receives a sequence of PCC frames containing point cloud media. The encoder may decide to encode such a frame, eg, in response to receiving a user command. In method 1100, the encoder determines that a first attribute should be encoded by a first codec while a second attribute is to be encoded by a second codec. good. This determination is based on a predetermined condition, for example when the first codec is more efficient for the first attribute and the second codec is more efficient for the second attribute. , and/or based on user input. Thus, the encoder encodes, at step 1101, a first attribute of a sequence of PCC frames into a bitstream having a first codec. Further, the encoder encodes a second attribute of the sequence of PCC frames into the bitstream at step 1103 with a second codec that is different from the first codec.

At step 1105, the encoder encodes various syntax elements into a bitstream along with the encoded video data. For example, the syntax elements can be coded into sequence level data units containing sequence level parameters to indicate to the decoder decisions made during encoding so that the PCC frame can be properly reconstructed. . Specifically, the encoder encodes the sequence-level data unit to indicate that the first attribute was encoded by the first codec and the second attribute was encoded by the second codec. Include a first syntactical element indicating that the As a particular example, a PCC frame may include multiple attributes including a first attribute and a second attribute. Also, the attributes of the PCC frame may include geometry, texture, and one or more of reflectance, transparency, and normal. Additionally, the first syntax element may be an identified_codec_for_attribute element included in a GOF header in the bitstream.

In some examples, the first attribute may be organized into multiple streams. In such cases, a second syntax element can be used to indicate stream membership for the bitstream data unit associated with the first attribute. In some examples, the first attribute may also be organized into multiple layers. In such cases, the third syntax element may indicate layer membership for the data unit of the bitstream associated with the first attribute. As a particular example, the second syntax element may be a num_streams_for_attribute element and the third syntax element may be a num_layers_for_attribute element, each of which may be included in a group of frame headers in the bitstream. In yet another example, a fourth syntax element may be used to indicate that a first of the multiple layers contains data associated with the irregular point cloud. As a particular example, the fourth syntax element may be a regular_points_flag element included in a group of frame headers in the bitstream.

By including such information in the sequence level data, the decoder may have sufficient information to decode the PCC video sequence. Thus, the encoder, in step 1107, uses the first attribute encoded by the first codec and the second attribute encoded by the second codec to support the generation of a decoded sequence of PCC frames. The bitstream may be transmitted based on the second attribute as well as other attributes and/or syntactical elements described herein.

FIG. 12 is a flowchart of an exemplary method 1200 for decoding a PCC video sequence with multiple codecs. For example, method 1200 can read data from a bitstream according to mechanism 800 while using attribute layers 931 , 932 , 933 and 934 and/or streams 1031 , 1032 , 1033 and/or 1034 . The method 1200 may also determine the mechanism used to encode attributes by reading the GOF header. Additionally, method 1200 may read PCC video stream 700 to reconstruct point-cloud media frames 600 and point-cloud media 500 . Additionally, method 1200 may be employed by codec system 200 and/or decoder 400 while performing the decoding steps of method 100 .

Method 1200 may begin at step 1201 when a decoder receives a bitstream containing a series of PCC frames. The decoder can then parse the bitstream or part thereof in step 1205 . For example, the decoder can parse the bitstream to obtain sequence-level data units that include sequence-level parameters. A sequence-level data unit may contain various syntactical elements that describe the encoding process. Thus, a decoder can parse the video data from the bitstream and use the syntax elements to determine the appropriate process for decoding the video data.

For example, a sequence-level data unit has a first syntax element indicating that a first attribute was encoded by a first codec and a second syntax element indicating that a second attribute was encoded by a second codec. can include As a particular example, a PCC frame may include multiple attributes including a first attribute and a second attribute. Also, the attributes of the PCC frame may include geometry, texture, and one or more of reflectance, transparency, and normal. Additionally, the first syntax element may be an identified_codec_for_attribute element included in a GOF header in the bitstream.

In some examples, the first attribute may be organized into multiple streams. In such cases, a second syntax element may be employed to indicate stream membership for the data unit of the bitstream associated with the first attribute. In some examples, the first attribute may also be organized into multiple layers. In such cases, the third syntax element may indicate layer membership for the data unit of the bitstream associated with the first attribute. As a specific example, the second syntax element may be a num_streams_for_attribute element and the third syntax element may be a num_layers_for_attribute element, each of which may be included in a group of frame headers in the bitstream. In yet another example, a fourth syntax element may be used to indicate that a first layer of the multiple layers contains data associated with the irregular point cloud. As a particular example, the fourth syntax element may be a regular_points_flag element included in a group of frame headers in the bitstream.

Thus, the decoder decodes the first attribute with the first codec and the second attribute with the second codec in step 1207 to generate a decoded sequence of PCC frames. be able to. The decoder also uses other attributes and/or syntax elements as described herein when determining the appropriate mechanism to employ when decoding various attributes of a PCC video sequence based on the codec. may be used.

FIG. 13 is a schematic diagram of an exemplary video coding device 1300. As shown in FIG. Video coding device 1300 is suitable for implementing the disclosed examples/embodiments as described herein. Video coding device 1300 includes a downstream port 1320, an upstream port 1350, and/or a transceiver unit 1310 that includes transmitters and/or receivers for communicating data upstream and/or downstream over a network. Video coding device 1300 also includes a processor 1330, which includes a logic unit and/or central processing unit (CPU), and memory 1332 for storing data. Video coding device 1300 may also be coupled to electrical, optical-electrical (OE) components, electrical-optical (EO) components, and/or upstream port 1350 and/or downstream port 1320 for electrical, optical, or wireless communication. A wireless communication component may be included for communicating data over a network. Video coding device 1300 may also include input and/or output (I/O) devices 1360 for communicating data to and from a user. The I/O devices 1360 may include output devices such as a display for displaying video data and speakers for outputting audio data. Input/output devices 1360 may also include input devices such as keyboards, mice, trackballs, etc. and/or corresponding interfaces for interacting with such output devices.

Processor 1330 is implemented by hardware and software. Processor 1330 may be implemented as one or more CPU chips, cores (eg, as a multicore processor), field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), and digital signal processors (DSPs). . Processor 1330 communicates with downstream port 1320 , Tx/Rx 1310 , upstream port 1350 and memory 1332 . Processor 1330 comprises a coding module 1314 . Coding module 1314 implements the disclosed embodiments described above, such as methods 100, 1100, 1200, 1500, and 1600, and mechanism 800, which code layers 931-934 and/or streams 1031-1034. Transformed point-cloud media 500, point-cloud media frames 600, and/or PCC video stream 700 may be employed. Coding module 1314 may also implement any other methods/mechanisms described herein. Additionally, coding module 1314 may implement codec system 200 , encoder 300 , and/or decoder 400 . For example, coding module 1314 can employ an extended attribute set for PCC with multiple streams and layers, and use such attribute sets within sequence-level data to support decoding. can be signaled. Coding module 1314 thus enables video coding device 1300 to provide additional functionality and/or flexibility when coding PCC video data. In this way, coding module 1314 improves the functionality of video coding device 1300 and addresses issues inherent in video coding technology. Further, coding module 1314 provides for converting video coding device 1300 to different states. Alternatively, coding modules 1314 may be implemented as instructions stored in memory 1332 and executed by processor 1330 (eg, as a computer program product stored on non-transitory media).

Memory 1332 may be a disk, tape drive, solid state drive, read only memory (ROM), random access memory (RAM), flash memory, ternary content addressable memory (TCAM), static random access memory (SRAM), or the like. Contains one or more memory types. Memory 1332 may be used as an overflow data storage device to store programs when the programs are selected for execution, and to store instructions and data read during program execution.

FIG. 14 is a schematic diagram of an exemplary system 1400 for coding PCC video sequences with multiple codecs. System 1400 includes a video encoder 1402 that includes a first attribute encoding module 1401 for encoding a first attribute of a sequence of PCC frames into a bitstream with a first codec. Video encoder 1402 further includes a second attribute encoding module 1403 for encoding a second attribute of the sequence of PCC frames into the bitstream with a second codec different from the first codec. The video encoder 1402 further includes a syntax encoding module 1405 for encoding sequence-level data units including sequence-level parameters into a bitstream, the sequence-level data units having a first attribute It includes a first syntax element indicating that it is encoded by one codec and that the second attribute is encoded by a second codec. Video encoder 1402 further supports generating a decoded sequence of PCC frames based on the first attribute encoded by the first codec and the second attribute encoded by the second codec. includes a transmission module 1407 for transmitting the bitstream to the . The modules of video encoder 1402 may also be employed to perform any of the steps/items described above with respect to methods 1100 and/or 1500.

System 1400 also includes a video decoder 1410 including a receiving module 1411 for receiving a bitstream containing a sequence of PCC frames. The video decoder 1410 further includes a parsing module 1413 for parsing the bitstream to obtain a sequence level data unit including sequence level parameters, the sequence level data unit being the first It includes a first syntax element indicating that the attribute was coded by a first codec and indicating that a second attribute of the PCC frame was coded by a second codec. The video decoder 1410 further includes a decoding module 1415 for decoding the first attribute with the first codec and the second attribute with the second codec to produce a decoded sequence of PCC frames. including. The modules of video decoder 1410 may also be employed to perform any of the steps/items described above with respect to methods 1200 and/or 1600.

FIG. 15 is a flowchart of another exemplary method 1500 for encoding a PCC video sequence with multiple codecs. For example, method 1500 can organize data into bitstreams according to mechanism 800 while using attribute layers 931, 932, 933 and 934 and/or streams 1031, 1032, 1033 and/or 1034. . The method 1500 may also specify the mechanism used to encode attributes within the GOF header. Additionally, method 1500 may generate PCC video stream 700 by encoding point-cloud media frames 600 based on point-cloud media 500 . Additionally, method 1500 may be employed by codec system 200 and/or encoder 300 while performing the encoding steps of method 100 .

At step 1501, multiple PCC attributes are encoded into a bitstream as part of a sequence of PCC frames. PCC attributes are encoded with multiple codecs. PCC attributes include geometry and texture. PCC attributes also include one or more of reflectance, transparency, and normal. Each coded PCC frame is represented by one or more PCC NAL units. At step 1503, an indication is encoded for each PCC attribute. This indication indicates the video codec used to encode the corresponding PCC attribute. At step 1505, the bitstream is transmitted towards the decoder.

FIG. 16 is a flowchart of another exemplary method 1600 for decoding a PCC video sequence with multiple codecs. For example, method 1600 can read data from a bitstream according to mechanism 800 while using attribute layers 931 , 932 , 933 and 934 and/or streams 1031 , 1032 , 1033 and/or 1034 . The method 1600 may also determine the mechanism used to encode attributes by reading the GOF header. Additionally, method 1600 may read PCC video stream 700 to reconstruct point-cloud media frames 600 and point-cloud media 500 . Additionally, method 1600 may be employed by codec system 200 and/or decoder 400 while performing the decoding steps of method 100 .

At step 1601, a bitstream is received. A bitstream includes a coded sequence of multiple PCC frames. A coded sequence of PCC frames represents multiple PCC attributes. PCC attributes include geometry and textures. PCC attributes also include one or more of reflectance, transparency, and normal. Each coded PCC frame is represented by one or more PCC NAL units. At step 1603, the bitstream is parsed to obtain, for each PCC attribute, an indication of the codec used to encode the corresponding PCC attribute. At step 1605, the bitstream is decoded based on the video codec indicated for the PCC attribute.

A first component is in contact with a second component when there are no intervening components except for lines, traces, or other media between the first component and the second component. Directly combined. A first component is indirectly connected to a second component when there is an intervening component other than a line, trace, or other medium between the first component and the second component. coupled to The term "bonding" and variations thereof includes both direct and indirect bonding. Use of the term "about" means a range including ±10% of the number that follows, unless otherwise specified.

Although several embodiments have been provided in this disclosure, it is understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of this disclosure. Yo. The examples are to be considered illustrative and not limiting, and the intent is not to be limited to the details given herein. For example, various elements or components may be combined or integrated into another system, or certain features may be omitted or not implemented.

Additionally, the techniques, systems, subsystems, and methods individually or separately described and illustrated in various embodiments may be incorporated into other systems, components, techniques, or methods without departing from the scope of the present disclosure. may be combined or integrated with Other examples of changes, substitutions, and modifications can be identified by those skilled in the art and may be made without departing from the spirit and scope disclosed herein.

Claims (28)

A method implemented by a decoder, comprising:
Receiving, by the decoder, a bitstream comprising an encoded sequence of multiple three-dimensional (3D) content frames, wherein the encoded sequence of multiple 3D content frames is a multiple of 3D content frames. representing attributes, each encoded 3D content frame being represented by one or more 3D content network abstraction layer (NAL) units;
for obtaining, by the decoder, for each 3D content attribute, an indication of one of a plurality of video coder decoders (codecs) used to encode the corresponding 3D content attribute; and parsing
decoding, by the decoder, the bitstream based on the indicated video codec for the 3D content attributes. Each sequence of three-dimensional (3D) content frames is associated with a sequence-level data unit including a sequence-level parameter, said sequence-level data unit having a first attribute encoded by a first video codec. and indicating that the second attribute was encoded by a second video codec. 3. The method of claim 2, wherein the first syntax element is an identified_codec_for_attribute element included in a group of frame headers in the bitstream. The first attribute is organized into a plurality of streams, a second syntax element indicating stream membership for data units of the bitstream associated with the first attribute, the second syntax element comprising: , a num_streams_for_attribute element contained in a group of frame headers in the bitstream. 5. Any of claims 1-4, wherein the first attribute is organized in a plurality of layers and a third syntax element indicates layer membership for data units of the bitstream associated with the first attribute. or the method described in paragraph 1. 6. The method of claim 5, wherein the third syntax element is a num_layers_for_attribute element included in a group of frame headers in the bitstream. A method according to any one of claims 1 to 6, wherein a fourth syntax element indicates that a first layer of said plurality of layers contains data associated with an irregular point cloud. . 8. The method of claim 7, wherein the fourth syntax element is a regular_points_flag element included in a group of frame headers in the bitstream. The bitstream is decoded into a decoded sequence of 3D content frames, and the method further comprises forwarding, by the decoder, the decoded sequence of 3D content frames towards a display for presentation. A method according to any one of claims 1 to 8, comprising A method implemented in an encoder, comprising:
encoding, by the encoder, multiple 3D content attributes of a sequence of multiple three-dimensional (3D) content frames into a bitstream with multiple coder-decoders (codecs), each encoded 3D a content frame is represented by one or more 3D content network abstraction layer (NAL) units;
encoding, by the encoder, for each 3D content attribute an indication of one of the video codecs used to encode the corresponding 3D content attribute;
and transmitting, by the encoder, the bitstream towards a decoder. Each sequence of 3D content frames is associated with a sequence-level data unit including sequence-level parameters, the sequence-level data unit having a first 3D content attribute encoded by a first video codec. and indicating that the second 3D content attribute was encoded by the second video codec. A method according to any one of claims 10 to 11, wherein said first syntax element is an identified_codec_for_attribute element contained in a group of frame headers in said bitstream. The first attribute is organized into a plurality of streams, a second syntax element indicating stream membership for data units of the bitstream associated with the first attribute, the second syntax element comprising: , a num_streams_for_attribute element contained in a group of frame headers in the bitstream. 14. The method of claim 13, wherein the first attributes are organized into multiple layers and a third syntax element indicates layer membership for data units of the bitstream associated with the first attributes. . A method according to any one of claims 10 to 14, wherein said third syntax element is a num_layers_for_attribute element included in a group of frame headers in said bitstream. A method according to any one of claims 10 to 15, wherein a fourth syntax element indicates that a first layer of said plurality of layers contains data associated with an irregular point cloud. . 17. The method of claim 16, wherein the fourth syntax element is a regular_points_flag element included in a group of frame headers in the bitstream. a decoding device,
a non-transitory memory storage device configured to store video data in the form of a bitstream;
a decoder configured to perform the method according to any one of claims 1-9. a non-transitory memory storage device configured to store video data in the form of a bitstream;
an encoder configured to perform the method of any one of claims 10-17. A non-transitory computer-readable medium containing computer-executable instructions stored on the non-transitory computer-readable medium, the video coding device comprising: A non-transitory computer-readable medium operable to carry out the method of any one of Claims 1 to 3. A decoder comprising processing circuitry for performing the method of any one of claims 1-9. An encoder comprising processing circuitry for performing the method of any one of claims 10-17. A non-transitory storage medium comprising a bitstream, said bitstream comprising an encoded sequence of three-dimensional (3D) content frames, said encoded sequence of 3D content frames comprising: , representing a plurality of 3D content attributes, each encoded 3D content frame being represented by one or more 3D content network abstraction layer (NAL) units, the bitstream comprising, for each 3D content attribute: The indicated video for the 3D content attribute parsed by a decoder to obtain an indication of one of a plurality of video coder decoders (codecs) used to encode the corresponding 3D content attribute. A non-transitory storage medium used to be decoded by said decoder based on a codec. A non-transitory storage medium comprising a bitstream, the bitstream encoding a plurality of 3D content attributes of a plurality of three-dimensional (3D) content frames into the bitstream by an encoder. wherein each encoded 3D content frame is represented by one or more 3D content network abstraction layer (NAL) units; and for each 3D content attribute, a corresponding 3D content attribute A non-transitory storage medium produced by: and encoding an indication of one of the video codecs used for encoding. an encoder,
encoding multiple 3D content attributes of a sequence of multiple three-dimensional (3D) content frames into a bitstream with multiple coder-decoders (codecs), each encoded 3D content frame first attribute encoding means and second attribute encoding means for performing encoding, represented by the above 3D content network abstraction layer (NAL) units;
syntax encoding means for encoding, for each 3D content attribute, an indication of one of the video codecs used to encode the corresponding 3D content attribute;
transmitting means for transmitting said bitstream towards a decoder. The encoder of claim 25, wherein the encoder is further configured to perform the method of any one of claims 10-17. Receiving a bitstream comprising an encoded sequence of multiple three-dimensional (3D) content frames, wherein the encoding sequence of multiple 3D content frames represents multiple 3D content attributes, each encoded receiving means for receiving the 3D content frame represented by one or more 3D content network abstraction layer (NAL) units;
parsing the bitstream to obtain, for each 3D content attribute, an indication of one of a plurality of video coder decoders (codecs) used to encode the corresponding 3D content attribute; an analytical means for performing
decoding means operable to decode the bitstream based on the indicated video codec for the 3D content attributes. Decoder according to claim 27, wherein the decoder is further arranged to perform the method according to any one of claims 1-9.

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